Generally, an electronic part such as a semiconductor package is mounted on a circuit board by a ball grid array (BGA) or the like. When such electronic part largely generates a heat, a heat radiating member such as a heat receiving block is pressingly abutted on the electronic part so that the electronic part is cooled through the heat radiating member. In this case, since the pressure from the heat radiating member is applied not only to the electronic part but also to the circuit board, the circuit board may be bent, and the electronic part may come off the circuit board.
There is a technology of preventing the bend of the circuit board by providing a reinforcing bracket that abuts on the circuit board (for example, JP-2003-110258-A). In JP-2003-110258-A, the bend of the circuit board and the coming off of an electronic part from the circuit board are prevented by providing a reinforcing bracket. The reinforcing bracket is fixed to a chassis of a personal computer while abutting on the rear surface of the circuit board, thereby supporting the circuit board and so as not to be bent by a load applied to the circuit board.
Sometimes, an opening may be provided in a circuit board where an electronic part is mounted. For example, a convex portion higher than the BGA may be present on the substrate side of an electronic part, and in order to prevent the convex portion from abutting on the circuit board, an opening is provided in the circuit board. Since strength of a circuit board around such opening is weak so as to be easily bent by a pressure from the heat radiating member, it is necessary to reinforce around the opening of the circuit board. However, in JP-2003-110258-A, no consideration is taken for an opening in the circuit board and for the bend of the circuit board around the opening.